174 Description of Plates 



PLATE XI. 



Figs. 31-33. Branchiomaldane vincenti Langerhans, from 

 near Cherbourg. 



Fig. 31. Adult, but rather contracted, specimen, 8 mm. long (see p. 148). 



Fig. 32. Anterior portion of an adult specimen, about 10 mm. long, stained 

 and cleared (see p. 152). 



Fig. 33. Posterior portion of a well-extended specimen, 10 5 mm. long, showing 

 the characteristic bi-armulate segments, in which the anterior ring 

 is chaetiferous and the posterior branchiferous. 



Figs. 34, 35. A. ecaudata Johnston, from near Cherbourg. 

 Fig. 34. Young, abranchiate post-larval specimen, 4'6 mm. long (see p. 80). 



Fig. 35. Fifteenth to twentieth segments of a late post-larval stage, 11 mm. 

 long, seen from the left side ; showing the gills on the sixteenth and 

 succeeding segments. Note that the gills are situated on the 

 respective chaetiferous annuli (cf. Fig. 33), and that the neuropodia 

 are much longer than those of Branchiomaldane (cf. Figs. 31, 33). 



PLATE XII. 

 Figs. 36-38. Nereis cultrifera Grube, from Plymouth. 



Figs. 36, 37. Dorsal (Fig. 36) and ventral (Fig. 37) views of the anterior end, 

 to show the pre-oral prostomium (Pr.), with its eyes, tentacles and 

 palps, the peristomium (Per.), with its cirri and the mouth, and the 

 first two chaetiferous segments, with their parapodia. 



Fig. 38. Parapodium or " foot," consisting of a basal piece and two distal, 

 lobate processes the iiotopodium and neuropodium each of which 

 bears a sensory cirrus, a bundle of chaetae (the tips of which project 

 from the mouth of the sac in which the chaetae were formed;, and 

 an aciculum, which serves as an internal skeleton. 



Figs. 39, 40. A. marina (Linnaeus). 



Fig. 39. Transverse section, passing through a parapodium, showing the noto- 

 podial chaetal sac, with its chaetae and its protractor and retractor 

 muscles, and the neuropoclial chaetal sac, with its crotchets 

 (see pp. 34, 35). 



Fig. 40. Anterior end, dorsal aspect; showing the buccal mass protruded, the 

 prostomium, nuchal groove, metastomial groove, and the openings 

 of the statocysts. From a specimen preserved with the anterior 

 end fully distended. 



PLATE XIII. 



Figs. 41, 42. A. cristata Stimpson (175 mm. long). The dorsal axis of the first 

 gill (Fig. 41) and of the fifth gill (Fig. 42). Pinnate type of gill (see 

 p. 58). 



Fig. 43. A. marina (Linnaeus), littoral form (120 mm. long), second left gill. 

 Fruticose or bushy type of gill (see pp. 58, 59). Most of the gill- 

 axes have been cut away near their origins. 



Fig. 44. A. pusilla Quatrefages (A claparedii Levinsen), from California. 

 A portion of the alimentary canal, at the junction of oesophagus and 

 stomach, to show the multiple oesophageal glands (see p. 63). The 

 posterior part of the oesophagus is contracted, and the glandular 

 caeca form a cluster. 



